This invention relates to a parts feeding device of the type utilized in a field where a feed rod is received in a guide tube so that it can be advanced and retracted and parts held in the feed rod are fed to an intended place for insertion into a receiving hole in a mating member.
This type of parts feeding device is disclosed in Japanese Patent Kokai No. 270075/92. It Is of the type in which a feed rod is received in a guide tube so that it can be advanced and retracted and parts held in the feed rod are fed to an intended place for insertion into a receiving hole in a mating member, wherein a parts feeding tube for feeding parts to the feed rod and the guide rod are joined together by a bracket having an air cylinder fixed thereto, said air cylinder being firmly joined to a stationary member. A part fed from the parts feeding tube to the feed rod and held at the front end of the feed rod is positioned immediately below a movable electrode which is a mating member by the air cylinder. Thereafter, the air cylinder is operated to move the part to the movable electrode, whereby the part is inserted in the receiving hole in the movable electrode.
In the arrangement in which the piston rod of the air cylinder is connected to the bracket which is used to join the guide tube and the parts feeding tube together, as described above, the load acting on the piston rod becomes imbalanced, preventing smooth operation of the air cylinder. That is, when the guide tube is heavier than the parts feeding tube, a bending load acts on said vertically disposed piston rod, making it difficult for the piston rod to slide smoothly. Particularly, since a part has to be inserted in the receiving hole in the movable electrode, said bending load impedes the correct relative positioning between the part and the receiving hole, making it impossible to insert the part. Even if the bending load on the piston rod is removed by joining the stationary member and the movable member by a guide groove, an abnormal force acts on the guide groove, thereby making it impossible to attain a smooth guide slide movement.